diff --git a/src/CBot/CBotStack.h b/src/CBot/CBotStack.h
index 61942dd2..c90d0bfe 100644
--- a/src/CBot/CBotStack.h
+++ b/src/CBot/CBotStack.h
@@ -276,7 +276,7 @@ public:
      *
      * in case of eventual break
      */
-    bool            BreakReturn(CBotStack* pfils, const std::string& name = nullptr);
+    bool            BreakReturn(CBotStack* pfils, const std::string& name = "");
     /**
      * \todo Document
      *